details of which taxes you plan to deal with, for example, Self Assessment (you may need a separate agent code for each tax)

Your application may be rejected if you don’t provide this information, or if HMRC isn’t reasonably satisfied with the information you have provided. HMRC will tell you if your application’s been successful or not within 28 days of receiving your application.

If you already have an HMRC Online Services account

Add ‘Corporation Tax for Agents’ to your portfolio from the ‘Services you can add’ section.

Getting agent authorisation through the Corporation Tax for Agents service

Once you’ve added the Corporation Tax for Agents service to your portfolio, you have to go through the agent authorisation process for any new or previously unauthorised client.

Log in to Corporation Tax for Agents and follow the instructions under ‘Request an authorisation’. You’ll need:

your client’s Corporation Tax Unique Taxpayer Reference number

either the postcode of your client’s registered office (main business address if no registered office) or their Companies House registration number

the authorisation code HMRC will send to your client’s registered office address by post - this code begins with ‘CT’ and you’ll need it to complete the authorisation process

The authorisation code can take up to 7 days to arrive. You’ll need to enter the code before the client will appear on your client list, so ideally you need to do this well in advance of their return filing deadline. You must enter the code within 30 days from the date on the letter.

Using the Corporation Tax for Agents service when the company is in receivership or liquidation

You can continue to use the service when the company is in receivership.

If the company is in liquidation, you won’t be able to use the service once HMRC has updated its records. However, the liquidator can use the service. They need to register the company for the service by following the process for registering a single company, but the address used in the registration process should be the liquidators.